forked from OSchip/llvm-project
112 lines
3.6 KiB
C++
112 lines
3.6 KiB
C++
//===-- runtime/utf.cpp ---------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "utf.h"
|
|
|
|
namespace Fortran::runtime {
|
|
|
|
// clang-format off
|
|
const std::uint8_t UTF8FirstByteTable[256]{
|
|
/* 00 - 7F: 7 bit payload in single byte */
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
|
/* 80 - BF: invalid first byte, valid later byte */
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
|
/* C0 - DF: 11 bit payload */
|
|
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
|
|
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
|
|
/* E0 - EF: 16 bit payload */
|
|
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
|
|
/* F0 - F7: 21 bit payload */ 4, 4, 4, 4, 4, 4, 4, 4,
|
|
/* F8 - FB: 26 bit payload */ 5, 5, 5, 5,
|
|
/* FC - FD: 31 bit payload */ 6, 6,
|
|
/* FE: 32 bit payload */ 7,
|
|
/* FF: invalid */ 0
|
|
};
|
|
// clang-format on
|
|
|
|
// Non-minimal encodings are accepted.
|
|
std::optional<char32_t> DecodeUTF8(const char *p0) {
|
|
const std::uint8_t *p{reinterpret_cast<const std::uint8_t *>(p0)};
|
|
std::size_t bytes{MeasureUTF8Bytes(*p0)};
|
|
if (bytes == 1) {
|
|
return char32_t{*p};
|
|
} else if (bytes > 1) {
|
|
std::uint64_t result{char32_t{*p} & (0x7f >> bytes)};
|
|
for (std::size_t j{1}; j < bytes; ++j) {
|
|
std::uint8_t next{p[j]};
|
|
if (next < 0x80 || next > 0xbf) {
|
|
return std::nullopt;
|
|
}
|
|
result = (result << 6) | (next & 0x3f);
|
|
}
|
|
if (result <= 0xffffffff) {
|
|
return static_cast<char32_t>(result);
|
|
}
|
|
}
|
|
return std::nullopt;
|
|
}
|
|
|
|
std::size_t EncodeUTF8(char *p0, char32_t ucs) {
|
|
std::uint8_t *p{reinterpret_cast<std::uint8_t *>(p0)};
|
|
if (ucs <= 0x7f) {
|
|
p[0] = ucs;
|
|
return 1;
|
|
} else if (ucs <= 0x7ff) {
|
|
p[0] = 0xc0 | (ucs >> 6);
|
|
p[1] = 0x80 | (ucs & 0x3f);
|
|
return 2;
|
|
} else if (ucs <= 0xffff) {
|
|
p[0] = 0xe0 | (ucs >> 12);
|
|
p[1] = 0x80 | ((ucs >> 6) & 0x3f);
|
|
p[2] = 0x80 | (ucs & 0x3f);
|
|
return 3;
|
|
} else if (ucs <= 0x1fffff) {
|
|
p[0] = 0xf0 | (ucs >> 18);
|
|
p[1] = 0x80 | ((ucs >> 12) & 0x3f);
|
|
p[2] = 0x80 | ((ucs >> 6) & 0x3f);
|
|
p[3] = 0x80 | (ucs & 0x3f);
|
|
return 4;
|
|
} else if (ucs <= 0x3ffffff) {
|
|
p[0] = 0xf8 | (ucs >> 24);
|
|
p[1] = 0x80 | ((ucs >> 18) & 0x3f);
|
|
p[2] = 0x80 | ((ucs >> 12) & 0x3f);
|
|
p[3] = 0x80 | ((ucs >> 6) & 0x3f);
|
|
p[4] = 0x80 | (ucs & 0x3f);
|
|
return 5;
|
|
} else if (ucs <= 0x7ffffff) {
|
|
p[0] = 0xf8 | (ucs >> 30);
|
|
p[1] = 0x80 | ((ucs >> 24) & 0x3f);
|
|
p[2] = 0x80 | ((ucs >> 18) & 0x3f);
|
|
p[3] = 0x80 | ((ucs >> 12) & 0x3f);
|
|
p[4] = 0x80 | ((ucs >> 6) & 0x3f);
|
|
p[5] = 0x80 | (ucs & 0x3f);
|
|
return 6;
|
|
} else {
|
|
p[0] = 0xfe;
|
|
p[1] = 0x80 | ((ucs >> 30) & 0x3f);
|
|
p[2] = 0x80 | ((ucs >> 24) & 0x3f);
|
|
p[3] = 0x80 | ((ucs >> 18) & 0x3f);
|
|
p[4] = 0x80 | ((ucs >> 12) & 0x3f);
|
|
p[5] = 0x80 | ((ucs >> 6) & 0x3f);
|
|
p[6] = 0x80 | (ucs & 0x3f);
|
|
return 7;
|
|
}
|
|
}
|
|
|
|
} // namespace Fortran::runtime
|